400 was what I started mine with. I never had the to work my way up.

Walmart quit after an hour and a half. At least I wasn't charged. It looks like now, it's time to hit the boneyards, although after I do get them where I want them. I will definitely try to protect them with the floor wax. Thanks for the tip.

 

I just happened to find the isle at Walmart that had the Wax and they had the pledge and another one as well all for about $7.00. I recall using this on the canopies of models that I put together. It also protects the plastics from crazing when using glues.
Another thing that may help is putting a clear film on it. something like window tint film.